NOTE:
We have the same problem here that we had with ULTM/TU 9: Old man Reed Richards is shown here leading the world-famous Fantastic Four, WAY before 21 year old Reed Richards gets his powers in the Ultimate universe.

For what it’s worth, this was published the same month as ULTSM 22, ULTM/TU 16 & ULTS 5. ULTFF 1 was published the same month as ULTSM 50, and ULTFF 21 (the issue where they finally go public and are called the “Fantastic Four”) was published the same month as ULTSM 79. Also, this can’t be moved forward because it happens on the same day as ULTS 3. And even then, as said above, Reed’s only 21 years old in the Ultimate Universe, so it doesn’t really matter anyway.

Back when we were working on the Ultimate Handbooks we were told to treat the special as being in continuity, except for the FF bits. And indeed, a few scenes, such as the Blade appearance, do get referred back to in other stories.